Method of making m-chlorobenzotrifluoride

Abstract

Disclosed is a method of making m-chlorobenzotrifluoride. Benzotrifluoride is reacted with chlorine gas in the presence of about 0.1 to about 5 mole % (based on benzotrifluoride) of a metal chloride which can be FeCl 3 , SbCl 3 , or AlCl 3 and about 0.025 to about 5.0 mole % (based on benzotrifluoride) of a catalyst having the formula ##STR1## where Z is halogen, alkyl from C 1 to C 6 , alkoxy from C 1 to C 6 , or fluoroalkyl from C 1 to C 6 , n is 0 to 5, and the molar ratio of metal chloride to cocatalyst is about 0.5 to about 4.

We claim: 
     
       1. A method of making m-chlorobenzotrifluoride comprising reacting benzotrifluoride with chlorine gas in the presence of about 0.1 to about 5 mole % (based on benzotrifluoride) of a metal chloride selected from the group consisting of FeCl 3 , SbCl 3 , AlCl 3 , and mixtures thereof and about 0.025 to about 5.0 mole % (based on benzotrifluoride) of a cocatalyst having the formula ##STR4## where Z is halogen, alkyl from C 1  to C 6 , alkoxy from C 1  to C 6 , or fluoroalkyl from C 1  to C 6 , n is 0 to 5, and the molar ratio of metal chloride to cocatalyst is about 0.5 to about 4. 
     
     
       2. A method according to claim 1 wherein said metal chloride is FeCl 3 . 
     
     
       3. A method according to claim 1 wherein Z is Cl, F, or CF 3 . 
     
     
       4. A method according to claim 1 wherein n is 0 or 1. 
     
     
       5. A method according to claim 1 wherein said cocatalyst is iodobenzene. 
     
     
       6. A method according to claim 1 wherein the amount of said metal chloride is about 0.2 to about 0.6 mole % (based on benzotrifluoride). 
     
     
       7. A method according to claim 1 wherein the amount of said cocatalyst is about 0.05 to about 1.2 mole % (based on benzotrifluoride). 
     
     
       8. A method according to claim 1 wherein the molar ratio of metal chloride to cocatalyst is about 1 to about 4. 
     
     
       9. A method according to claim 1 wherein the amount of said chlorine gas is about 0.7 to about 1.1 equivalents. 
     
     
       10. A method according to claim 1 wherein the reaction temperature is about -10° to about 40° C. 
     
     
       11. A method according to claim 1 including the additional last steps of purging the product of said reaction with nitrogen to remove HCl, flash distilling at atmospheric or reduced pressure to remove FeCl 3 , passing the distillate through carbon, alumina, magnesium oxide, or copper to remove trace inorganic iodides, and distilling to separate m-chlorobenzotrifluoride and p-chlorobenzotrifluoride from o-chlorobenzotrifluoride and recover unreacted benzotrifluoride. 
     
     
       12. A method according to claim 1 wherein said cocatalyst is m-iodobenzotrifluoride. 
     
     
       13. A method according to claim 1 where said cocatalyst is recovered and re-used. 
     
     
       14. A method of making m-chlorobenzotrifluoride comprising passing chlorine gas through benzotrifluoride in the presence of (1) about 0.2 to about 0.6 mole % (based on benzotrifluoride) of ferric chloride; and   (2) about 0.05 to about 1.2 mole % (based on benzotrifluoride) of a cocatalyst having the formula ##STR5## where Z is F or CF 3 , n is 0 or 1, and the molar ratio of ferric chloride to cocatalyst is about 1 to about 2.   
     
     
       15. A method according to claim 14 wherein the reaction temperature is about -10° to about 40° C. 
     
     
       16. A method according to claim 14 including the additional last steps of purging the product of said reaction with nitrogen to remove HCl, flash distilling at atmospheric or reduced pressure to remove FeCl 3 , passing the distillate through carbon, alumina, magnesium oxide, or copper to remove trace inorganic iodides, and distilling to separate m-chlorobenzotrifluoride and p-chlorobenzotrifluoride from o-chlorobenzotrifluoride and recover unreacted benzotrifluoride. 
     
     
       17. A method according to claim 14 wherein the amount of said chlorine gas is about 0.7 to about 1.1 equivalents. 
     
     
       18. A method of making m-chlorobenzotrifluoride comprising (A) forming a composition of (1) benzotrifluoride;   (2) about 0.2 to about 0.6 mole % (based on benzotrifluoride) of ferric chloride; and   (3) about 0.05 to about 1.2 mole % (based on benzotrifluoride) of m-iodobenzotrifluoride, where the molar ratio of ferric chloride to m-iodobenzotrifluoride is about 1 to about 4 and the temperature of said composition is about -10° to about 40° C.;     (B) reacting about 0.7 to about 1.1 equivalents of chlorine gas with said benzotrifluoride;   (C) removing solids from said composition; and   (D) removing said m-chlorobenzotrifluoride by distillation.   
     
     
       19. A method according to claim 18 wherein said solids are removed by passing said composition through carbon, alumina, magnesium oxide, or copper. 
     
     
       20. A method according to claim 18 wherein said composition is passed through activated carbon, alumina, magnesium oxide, or copper prior to said distillation.